(1) Field of the Invention
The present invention relates to a device for improving the readout accuracy of precision measuring instruments and more particularly to a bearing support ditherer which acts to replace static bearing friction with the corresponding lower value of dynamic friction by selectively vibrating the bearing mount so as to produce a random or pseudo-random rotary planar motion of the bearing.
(2) Description of the Prior Art
It is well known that readout accuracies of high quality measuring instruments such as compasses are limited by the finite friction of their bearings. This bearing friction can be reduced by vibrating the instrument, thereby causing static bearing friction to be replaced by a lower value of dynamic friction. Modern quantized instrument electrical readouts have the capability of providing accuracies much greater than now obtainable mechanically due to the presence of such static bearing friction. The static friction of precise bearings has been previously reduced by; use of jeweled bearings, vibrating the entire sensing unit in order to pass motion to the bearing or by periodic or randomized dynamic altering (movement) of the sensing unit or of the force field being sensed followed by averaging the readout. Further, because compass readout accuracy is generally proportional to physical size, reduction of bearing friction is required in order to permit production of smaller units which have the readout accuracy of present larger units.